Ruin
Middle English (in the sense ‘collapse of a building’): from Old French ruine, from Latin ruina, from ruere ‘to fall’.
wiktionary
From Middle English ruyne, ruine, from Old French ruine, from Latin ruīna(“overthrow, ruin”), from ruō(“I fall down, tumble, sink in ruin, rush”).
etymonline
ruin (n.)
late Old English, "act of giving way and falling down" (a sense now obsolete), from Latin ruina "a collapse, a rushing down, a tumbling down" (source also of Old French ruine "a collapse," Spanish ruina, Italian rovina), which is a derivative of ruere "to rush, fall violently, collapse" (from PIE *reue- (2) "to smash, knock down, tear out, dig up;" see rough (adj.)).
The sense of "descent from a state of prosperity, degradation, downfall or decay of a person or society" is from late 14c. The general meaning "violent or complete destruction" (of anything), "a profound change so as to unfit a thing for use" (of one's principles, one's shirt, etc.) is by 1670s; the sense of "that which causes destruction or downfall" is from early 15c. The meaning "dishonor," of a woman, is from 1620s. Ruins "remains of a decayed building or town" is from mid-15c.; the same sense was in the Latin plural noun.
ruin (v.)
1580s, "reduce (a place) to ruin," transitive, from ruin (n.) or from French ruiner (14c.). From 1610s as "inflict disaster upon" (someone). The meaning "bring to ruin, damage essentially and irreparably" is by 1650s. The intransitive sense of "fall into ruin" is from c. 1600, now rare or obsolete. The financial sense of "reduce to poverty, wreck the finances of" is attested from 1650s. Related: Ruined; ruining.
